Plug-in hybrid electric vehicles (PHEV) and electric vehicles (EV) mounted with an AC-DC converter that converts alternating-current voltage (hereinafter also referred to as AC voltage) supplied from a commercial power supply for household use into direct-current voltage (hereinafter also referred to as DC voltage) and having a battery charged with the DC voltage converted by the AC-DC converter have been widespread.
Japanese Patent Application Laid-Open Publication No. 2009-213202 discloses an AC-DC converter converting AC voltage into DC voltage. The AC-DC converter comprises an AC-DC converter provided with a power factor correction (PFC) circuit and an insulating DC-DC converter. Between the AC-DC converter with the PFC circuit (hereinafter also referred to as “PFC-added AC-DC converter”) and the DC-DC converter, a capacitor for reducing ripple voltage is interposed. The DC-DC converter includes an isolation transformer, a full bridge circuit provided at the preceding stage of the isolation transformer, and a diode bridge provided at the succeeding stage thereof.
The PFC-added AC-DC converter raises and rectifies the AC voltage for the commercial power supply. The voltage rectified at the PFC-added AC-DC converter is converted into the AC voltage of high frequency by the full bridge circuit. The converted AC voltage is converted into DC voltage of battery voltage by the rectifying circuit and the smoothing circuit through the isolation transformer.